A liquid can be slowly and steadily drained through a single opening in a container by tilting the container so that air can also flow into the container through the opening to fill the volume occupied by the liquid flowing out of the container. However, in an effort to increase the flow rate of the liquid from the container, one typically inverts the container but the liquid contents block the opening, preventing air from entering the container. As a result, a vacuum forms within the container which is repeatedly released when small amounts of the liquid falls through the opening followed by corresponding volumes of air that rapidly rush into the container through the same opening, briefly stopping the flow of the liquid. This repeated interruption in the flow of the liquid causes the container to jolt up and down and sideways as the mass of the liquid contents rapidly changes with each quick release of a small amount of the liquid through the opening. The jolts subside and a smooth steady flow of the liquid eventually occurs after much of the liquid is emptied and can no longer prevent the flow of air into the container.